Method of manufacturing a wrap around shield for a perpendicular write pole using a laminated mask with an endpoint detection layer

ABSTRACT

A method for manufacturing a magnetic write pole and trailing wrap around magnetic shield for use in a perpendicular magnetic data recording system. The method includes the use of a hard mask structure with end point detection material embedded in a hard mask material. The novel hard mask structure provides the mill resistance of a hard mask, with the end point detection advantages of an end point detection layer.

FIELD OF THE INVENTION

The present invention relates to perpendicular magnetic recording andmore particularly to a novel trailing wrap around magnetic shield designand a method for manufacturing such a shield design.

BACKGROUND OF THE INVENTION

The heart of a computer's long term memory is an assembly that isreferred to as a magnetic disk drive. The magnetic disk drive includes arotating magnetic disk, write and read heads that are suspended by asuspension arm adjacent to a surface of the rotating magnetic disk andan actuator that swings the suspension arm to place the read and writeheads over selected circular tracks on the rotating disk. The read andwrite heads are directly located on a slider that has an air bearingsurface (ABS). The suspension arm biases the slider toward the surfaceof the disk, and when the disk rotates, air adjacent to the disk movesalong with the surface of the disk. The slider flies over the surface ofthe disk on a cushion of this moving air. When the slider rides on theair bearing, the write and read heads are employed for writing magnetictransitions to and reading magnetic transitions from the rotating disk.The read and write heads are connected to processing circuitry thatoperates according to a computer program to implement the writing andreading functions.

The write head traditionally includes a coil layer embedded in first,second and third insulation layers (insulation stack), the insulationstack being sandwiched between first and second pole piece layers. A gapis formed between the first and second pole piece layers by a gap layerat an air bearing surface (ABS) of the write head and the pole piecelayers are connected at a back gap. Current conducted to the coil layerinduces a magnetic flux in the pole pieces which causes a magnetic fieldto fringe out at a write gap at the ABS for the purpose of writing theaforementioned magnetic transitions in tracks on the moving media, suchas in circular tracks on the aforementioned rotating disk.

In recent read head designs a spin valve sensor, also referred to as agiant magnetoresistive (GMR) sensor, has been employed for sensingmagnetic fields from the rotating magnetic disk. The sensor includes anonmagnetic conductive layer, hereinafter referred to as a spacer layer,sandwiched between first and second ferromagnetic layers, hereinafterreferred to as a pinned layer and a free layer. First and second leadsare connected to the spin valve sensor for conducting a sense current,therethrough. The magnetization of the pinned layer is pinnedperpendicular to the air bearing surface (ABS) and the magnetic momentof the free layer is located parallel to the ABS, but free to rotate inresponse to external magnetic fields. The magnetization of the pinnedlayer is typically pinned by exchange coupling with an antiferromagneticlayer.

The thickness of the spacer layer is chosen to be less than the meanfree path of conduction electrons through the sensor. With thisarrangement, a portion of the conduction electrons is scattered by theinterfaces of the spacer layer with each of the pinned and free layers.When the magnetizations of the pinned and free layers are parallel withrespect to one another, scattering is minimal and when themagnetizations of the pinned and free layer are antiparallel, scatteringis maximized. Changes in scattering alter the resistance of the spinvalve sensor in proportion to cos Θ, where Θ is the angle between themagnetizations of the pinned and free layers. In a read mode theresistance of the spin valve sensor changes proportionally to themagnitudes of the magnetic fields from the rotating disk. When a sensecurrent is conducted through the spin valve sensor, resistance changescause potential changes that are detected and processed as playbacksignals.

When a spin valve sensor employs a single pinned layer it is referred toas a simple spin valve. When a spin valve employs an antiparallel (AP)pinned layer it is referred to as an AP pinned spin valve. An AP spinvalve includes first and second magnetic layers separated by a thinnon-magnetic coupling layer such as Ru. The thickness of the spacerlayer is chosen so as to be antiparallel coupled to the magnetizationsof the ferromagnetic layers of the pinned layer. A spin valve is alsoknown as a top or bottom spin valve depending upon whether the pinninglayer is at the top (formed alter the free layer) or at the bottom(before the free layer).

The spin valve sensor is located between first and second nonmagneticelectrically insulating read gap layers and the first and second readgap layers are located between ferromagnetic first and second shieldlayers. In a merged magnetic head a single ferromagnetic layer functionsas the second shield layer of the read head and as the first pole piecelayer of the write head. In a piggyback head the second shield layer andthe first pole piece layer are separate layers.

Magnetization of the pinned layer is usually fixed by exchange couplingone of the ferromagnetic layers (API) with a layer of antiferromagneticmaterial such as PtMn. While an antiferromagnetic (AFM) material such asPtMn does not in and of itself have a magnetization, when exchangecoupled with a magnetic material, it can strongly pin the magnetizationof the ferromagnetic layer.

In order to meet the ever increasing demand for improved data rate anddata capacity, researchers have recently been focusing their efforts onthe development of perpendicular recording systems. A traditionallongitudinal recording system, such as one that incorporates the writehead described above, stores data as magnetic bits orientedlongitudinally along a track in the plane of the surface of the magneticdisk. This longitudinal data bit is recorded by a fringing field thatforms between the pair of magnetic poles separated by a write gap.

A perpendicular recording system, by contrast, records data asmagnetizations oriented perpendicular to the plane of the magnetic disk.The magnetic disk has a magnetically soft underlayer covered by a thinmagnetically hard top layer. The perpendicular write head has a writepole with a very small cross section and a return pole having a muchlarger cross section. A strong, highly concentrated magnetic field emitsfrom the write pole in a direction perpendicular to the magnetic disksurface, magnetizing the magnetically hard top layer. The resultingmagnetic flux then travels through the soft underlayer, returning to thereturn pole where it is sufficiently spread out and weak that it willnot erase the signal recorded by the write pole when it passes backthrough the magnetically hard top layer on its way back to the returnpole.

One of the features of perpendicular recording systems is that the highcoercivity top layer of the magnetic medium has a high switching field.This means that a strong magnetic field is needed to switch the magneticmoment of the medium when writing a magnetic bit of data. In order todecrease the switching field and increase recording speed, attempts havebeen made to angle or “cant” the write field being emitted from thewrite pole. Canting the write field at an angle relative to the normalof the medium makes the magnetic moment of the medium easier to switchby reducing the switching field. Modeling has shown that a single polewriter in a perpendicular recording system can exhibit improvedtransition sharpness (i.e. better field gradient and resolution),achieve better media signal to noise ratio, and permit higher coercivefield media for higher areal density magnetic recording if, according tothe Stoner-Wohlfaith model for a single particle, the effective fluxfield is angled. A method that has been investigated to cant themagnetic field has been to provide a trailing magnetic shield adjacentto the write head, to magnetically attract the field from the writepole.

The trailing shield can be a floating design, in that the magnetictrailing shield is not directly, magnetically connected with the otherstructures of the write head. Magnetic field from the write pole resultsin a flux in the shield that essentially travels through the magneticmedium back to the return pole of the write head. Alternatively, thetrailing shield can be magnetically connected with other magneticportion of the write head such as the write pole and return pole.

Various dimensions of the shield are critical for the trailing shield tooperate correctly. For instance, effective angling or canting of theeffective flux field is optimized when the write pole to trailing shieldseparation (gap) is about equal to the head to soft underlayer spacing(HUS) and the trailing shield throat height is roughly equal to half thetrack-width of the write pole. This design improves write field gradientat the expense of effective flux field. To minimize effective flux fieldlost to the trailing shield and still achieve the desired effect, thegap and shield thickness are adjusted to minimize saturation at theshield and effective flux field lost to the shield respectively. Inorder for a trailing shield to function optimally, the thickness of thetrailing shield gap must be tightly controlled. Therefore, there is aneed for a means for accurately controlling such trailing gap thicknessduring manufacture.

In addition, the track width and shape of the write pole must be tightlycontrolled. The write pole is preferably configured with a trapezoidalshape and preferably has a straight fiat trailing edge. The write polecan be formed by ion milling a magnetic material at such an angle orcombination of angles that a write pole having the desired trapezoidalshape is formed. A challenge to creating such a well defined polestructure is that the mask used during ion milling must be thick androbust to withstand the aggressive ion mill and form a write pole havinga well controlled track width and flat, straight trailing edge. Such amask structure does not lend itself well to functioning as a trailingshield gap, because, alter the ion milling, the remaining mask is notflat and does not have the desired small, well controlled thickness tofunction as a trailing shield gap.

Therefore, there is a need for a method for manufacturing aperpendicular write head that can produce a write pole having a wellcontrolled track width and flat trailing edge, while still producing atrailing, wrap around shield that has a trailing gap with a wellcontrolled thickness and shape.

SUMMARY OF THE INVENTION

The present invention provides a method for manufacturing a magneticwrite head for perpendicular recording having a wrap around trailingshield. The method includes depositing a magnetic write pole materialover a substrate and then forming mask structure over the magnetic writepole material. The mask structure includes a hard mask-layer with an endpoint detection layer embedded therein at a desired elevation within thehard mask layer. The end point detection layer can be a material that isessentially the same as the rest of the hard mask except with a smallamount of an easily detectable element added therein.

An ion milling operation is performed to remove magnetic write polematerial not covered by the mask structure, to form the write pole. Anon-magnetic material is then deposited and a reactive ion mill isperformed to remove the non-magnetic material until the end pointdetection layer has been reached and removed.

The present invention provides end point detection while reducing thenumber of mask layers that, must be deposited, while maximizing theamount of ion mill resistant, material in the hard mask structure. Theinvention uses innovative hard mask materials, which have the end pointdetection marker embedded in the hard mask material inlow-concentration. In this way, the hard mask material retains its lowion mill rate properties while also serving as an end point detectionmarker.

These and other features and advantages of the invention will beapparent upon reading of the following detailed description of preferredembodiments taken in conjunction with the Figures in which likereference numerals indicate like elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of thisinvention, as well as the preferred mode of use, reference should bemade to the following detailed description read in conjunction with theaccompanying drawings which are not to scale.

FIG. 1 is a schematic illustration of a disk drive system in which theinvention might be embodied;

FIG. 2 is an ABS view of a slider, taken from line 2-2 of FIG. 1,illustrating the location of a magnetic head thereon;

FIG. 3 is a cross sectional view, taken from line 3-3 of FIG. 2 androtated 90 degrees counterclockwise, of a magnetic head according to anembodiment of the present invention;

FIG. 4 is an ABS view of the write head taken from line 4-4 of FIG. 3

FIG. 5 is an enlarged view of a write pole and surrounding structure;

FIGS. 6-15 are ABS views similar to that of FIGS. 4 and 5, showing amagnetic head in various intermediate stages of manufacture andillustrating a method of manufacturing a magnetic head according to anembodiment of the invention; and

FIGS. 16-18 are views of a magnetic write head in various intermediatestages of manufacture illustrating a method of manufacturing a writehead according to an alternate embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is of the best embodiments presentlycontemplated for carrying out this invention. This description is madefor the purpose of illustrating the general principles of this inventionand is not meant to limit the inventive concepts claimed herein.

Referring now to FIG. 1, there is shown a disk drive 100 embodying thisinvention. As shown in FIG. 1, at least one rotatable magnetic disk 112is supported on a spindle 114 and rotated by a disk drive motor 118. Themagnetic recording on each disk is in the form of annular patterns ofconcentric data tracks (not shown) on the magnetic disk 112.

At least one slider 113 is positioned near the magnetic disk 112, eachslider 113 supporting one or more magnetic head assemblies 221. As themagnetic disk rotates, slider 113 moves radially in and out over thedisk surface 122 so that the magnetic head assembly 121 may accessdifferent tracks of the magnetic disk where desired data, are written.Each slider 113 is attached to an actuator arm 119 by way of asuspension 115. The suspension 115 provides a slight spring force whichbiases slider 113 against the disk, surface 122. Each actuator arm 119is attached to an actuator means 127. The actuator means 127 as shown inFIG. 1 may be a voice coil motor (VCM). The VCM comprises a coil movablewithin a fixed magnetic field, the direction and speed of the coilmovements being controlled by the motor current signals supplied bycontroller 129.

During operation of the disk storage system, the rotation of themagnetic disk 112 generates an air bearing between the slider 113 andthe disk surface 122 which exerts an upward force or lift on the slider.The air bearing thus counter-balances the slight spring force ofsuspension 115 and supports slider 113 off and slightly above the disksurface by a small, substantially constant spacing during normaloperation.

The various components of the disk storage system are controlled inoperation by control signals generated by control unit 129, such asaccess control signals and internal clock signals. Typically, thecontrol unit 129 comprises logic control circuits, storage means and amicroprocessor. The control unit 129 generates control signals tocontrol various system operations such as drive motor control signals online 123 and head position and seek control signals on line 128. Thecontrol signals on line 128 provide the desired current profiles tooptimally move and position slider 113 to the desired data track on disk112. Write and read signals are communicated to and from write and readheads 121 by way of recording channel 125.

With reference to FIG. 2, the orientation of the magnetic head 121 in aslider 113 can be seen in more detail. FIG. 2 is an ABS view of theslider 113, and as can be seen the magnetic head including an inductivewrite head and a read sensor, is located at a trailing edge of theslider. The above description of a typical magnetic disk storage system,and the accompanying illustration of FIG. 1 are for representationpurposes only. It should be apparent that disk storage systems maycontain a large number of disks and actuators, and each actuator maysupport a number of sliders.

With reference now to FIG. 3, the magnetic head 221 for use in aperpendicular magnetic recording system is described. The head 221includes a write element 302 and a read element 304 that includes amagnetoresistive sensor 305. The read sensor 305 is preferably a giantmagnetoresistive (GMR) sensor and is preferably a current perpendicularto plane (CPP) GMR sensor. CPP GMR sensors are particularly well suitedfor use in perpendicular recording systems. However, the sensor 305could be another type of sensor such as a current in plane (CIP) GMRsensor or, a tunnel junction sensor (TMR) or some other type of sensor.The sensor 305 is located between and insulated from first and secondmagnetic shields 306, 308 and embedded in a dielectric material 307. Themagnetic shields, which can be constructed of for example CoFe or NiFe,absorb magnetic fields, such as those from up-track or down track datasignals, ensuring that the read sensor 304 only detects the desired datatrack located between the shields 306, 308. A non-magnetic, electricallyinsulating gap layer 309 may be provided between the shield 308 and thewrite head 302.

With continued reference to FIG. 3, the write element 302 includes awrite pole 310 that is magnetically connected with a magnetic shapinglayer 312, and is embedded within an insulation material 311. The writepole 310 has a small cross section at the air bearing surface and isconstructed of a material having a high saturation moment, such as NiFeor CoFe. The shaping layer 312 is constructed of a magnetic materialsuch as CoFe or NiFe.

The write element 302 also has a return pole 314 that preferably has asurface exposed at the ABS and has a cross section parallel with the ABSsurface that is much larger than that of the write pole 310. This can beseen more clearly with reference to FIG. 4, which shows the head 221 asviewed from the air bearing surface (ABS). The return pole 314 ismagnetically connected with the shaping layer 312 by a back gap portion316. The return pole 314 and back gap 316 can be constructed of, forexample, NiFe, CoFe or some other magnetic material.

An electrically conductive write coil 317, shown in cross section inFIG. 3, passes through the write element 302 between the shaping layer312, and the return pole 314. The write coil 317 is surrounded by anelectrically insulating material 320 that electrically insulates theturns of the coil 317 from one another and electrically isolates thecoil 317 from the surrounding magnetic structures 310, 312, 316, 314.When a current passes through the coil 317, the resulting magnetic fieldcauses a magnetic flux to flow through the return pole 314, back gap316, shaping layer 312 and write pole 310. This magnetic flux causes awrite field to be emitted toward an adjacent magnetic medium (not shownin FIGS. 3 and 4). The shaping layer 312 is also surrounded by aninsulation layer 321 which separates the shaping layer 312 from the ABS.The insulation layers 320, 321, 311 can all be constructed of the samematerial, such as alumina (Al₂0₃) or of different electricallyinsulating materials.

The write head element 302 also includes a trailing shield 322. Withreference to FIG. 4, the trailing shield 322 wraps around the write pole310 to provide side shielding as well as trailing shielding from straymagnetic fields. These stray magnetic fields can be from portions of thewrite head 302 itself, or could also be from adjacent track signals orfrom magnetic fields from external sources.

With reference now to FIG. 5 the configuration of the write pole 310 andthe surrounding portions of the trailing shield 322 are shown enlargedand in greater detail. The write pole 310 has a trailing edge 402 and aleading edge 404. The terms trailing and leading are with respect to thedirection of travel along a data track when the write head 302 is inuse. The write pole 310 also preferably has first and second laterallyopposing sides 406, 408 that are configured to define a width at theleading edge 404 that is narrower than the width at the trailing edge402, forming a write pole 310 having a trapezoidal shape. Thistrapezoidal shape is useful in preventing adjacent track writing due toskew of the write head 302 when the head 302 is located at extreme outeror inner positions over the disk, however, this trapezoidal shape of thewrite head 310 is not necessary to practice the present invention.

With continued reference to FIG. 5, the magnetic trailing shield 322 isseparated from each side 406, 408 of the write pole 310 by a side gap410. The trailing shield 322 is also separated from the trailing edge402 of the write pole 310 by a trailing gap 412. The thickness of eachof the side gaps 410 is preferably about 2 to 4 or about 3 times thethickness of the trailing gap 412. The materials defining and fillingthe side and trailing gaps 410, 412 are non-magnetic materials. Thetrailing gap 412 is filled with a non-magnetic material 416, which maybe alumina or may be some other non-magnetic material. Similarly, theside gaps 410 include a non-magnetic side gap material 414 which may be,for example, conformally deposited alumina.

As can be seen with reference to FIG. 5, the trailing shield 322 may ormay not be configured with notches 418 at either side of the write pole310. The notches can be described as extensions of the side gaps 410that extend in the trailing direction slightly beyond the trailing edgegap 412. These optional notches 418 can be constructed by amanufacturing process that will be described below, and can improve themagnetic performance of the write element 302. Preferably the notcheshave a notch depth (ND) that is less than or equal to 30 nm. Thetrailing shield 322 can be constructed, of a magnetic material such asNiFe.

With reference now to FIGS. 6 through 15, a method for constructing awrite pole and a wrap around trailing shield according to an embodimentis described. The method described with reference to FIGS. 6-15 can forma trailing shield with notches 418 and with a very well controlledtrailing gap thickness 412 as described above with reference to FIG. 5.

With particular reference to FIG. 6, a substrate layer 600 is provided.The substrate 600 can include the non-magnetic fill layer 321 and theshaping layer 312 on which the write pole 310 is to be formed (FIG. 3).One or more layers of write pole material 602 are deposited over thesubstrate 600. The write pole layer 604 preferably is a lamination ofmagnetic layers such as CoFe with thin layers of non-magnetic materialsandwiched between the magnetic layers.

A plurality of mask layers 604 are deposited over the write pole layer(lamination) 602. The mask layers include a first hard mask structure603. The first hard mask layer 603 includes a first sub-layer 606constructed of a material that has a high resistance ion milling,preferably alumina (Al₂O₃). The first sub-layer is constructed to athickness to define a trailing gap thickness in the finished trailingshield. For example, the first sub-layer 606 can be constructed to athickness of 15-25 nm or about 20 nm. The first hard mask layer furtherincludes a second sub-layer 608. The second sub-layer is preferablyconstructed of a material that is resistant to ion milling, but isremoval by a process such as reactive ion etching (RIE). The secondsub-layer 608 can, therefore, be constructed of, for example, Si₃N₄. Thesecond sub-layer 608 (which can also be referred to as a RIEable layer)has a thickness that is chosen to define the size of a trailing shieldnotch such as the notch 418 described with reference to FIG. 5.Therefore, the second sub-layer 608 can have a thickness of 25-35 nm orabout 30 nm. In addition, the first hard mask layer 603 includes a thirdsub-layer 610. The third sub-layer is constructed of a material thatfunctions both as a hard mask material and also as an end pointdetection layer. Therefore, the third sub-layer 610 should beconstructed of a material that can be easily detected, such as bySecondary Ion Mass Spectroscopy (SIMS) and which also is very resistantion milling. The third sub-layer can, therefore, be constructed of hardmask material such as alumina with a small amount of a detectablematerial such as Ti, (ie. AlTiO). The third sub-layer 610 can have, forexample 2-10 atomic percent or about 5 atomic percent Ti. The use ofalumina in the hard mask sub-layers 606, 610 is by way of example only,however. Other hard ion mill resistant materials such as Diamond LikeCarbon (DLC), BeO, etc. could be used as well. In addition, the use ofTi as a detectable material in the third sub-layer is by way of exampleonly. The detectable material element can be any element on the periodictable that does not have isotopic overlap with the milling gas (used ina reactive ion milling operation to be described below), atmosphericgases nor the layers below the hard mask layer. Other detectablematerials that could be used include Ta, V, Cr, Cu, Zr, Nb, Mo, Ru, Rh,Hr, W, Re, Os, Ir, Pt and Au. The third sub-layer advantageouslymaintains the hard mask properties of it majority material (for examplealumina) while also being detectable by the incorporation of a smallamount of detectable material.

With continued reference to FIG. 6, the mask layers 604 further includea first image transfer layer 612, which can be a soluble polyimide layersuch as DURIMIDE®. The first image transfer layer can be, for example,1000 to 1400 nm or about 1200 nm. Another hard mask layer 614 such as,for example silicon dioxide (SiO₂) can be deposited over the first imagetransfer layer, and an antireflective layer 616, which can also be asoluble polyimide such as DURIMIDE® can be formed over the second hardmask 614. The top hard mask 614 can be 60 to 1.50 nm thick or about 90nm thick. The second, or top, image transfer layer 616 can be 100 to 130nm thick or about 115 nm thick. A layer of resist material such asphotoresist or e-beam resist 618 is deposited at the top of the masklayers 604.

With reference now to FIG. 7, the resist layer is photolithographic-allypatterned, such as by photolithography or electron beam (e-beam)lithography. After exposure, the photo layer is developed in anappropriate developing solution. The photo layer 618 is patterned tohave a width to define a desired write pole track width, as will befurther described herein below.

With reference now to FIG. 8, a reactive ion etch (RIE) 802 is performedto transfer the image of the photoresist mask 618 onto the underlyingimage transfer layers 612, 618 and top hard mask 616, by removingportions of the layers that are not covered by the photo mask 802. TheRIE 802 can be performed in several steps using both oxygen chemistrysuch as O₂ and CO₂ and fluorine chemistry such as a CF₄ or CHF₃. Then,with reference to FIG. 9, a reactive ion mill 902 is performed totransfer the image of the overlying mask layers 612, 614, 616 and 618onto the underlying first hard mask structure 603. The reactive ionmilling 902 can be performed with an Ar or CHF₃ based process dependingon the materials used in the hard mask layers 606, 610 and end pointdetection layer 608. The above described material removal processes areby way of example, however. The choice of which material removalprocesses are used to transfer the image of the photo layer 618 onto theunderlying mask layers 606-616 will depend upon the materials used forthese layers 606-616.

With reference now to FIG. 10, an ion milling operation 1002 isperformed to remove portions of the write pole material 602 that are notprotected by the mask layers 604. The ion milling is preferablyperformed at an angle (or various angles) with respect to normal inorder to configure the write pole 602 with the desired trapezoidal shapeas shown. This is, however, not necessary to the practice of the presentinvention. It can be seen that the ion milling 1002 removes the photolayer 618 top image transfer layer 616 top hard mask 614 and at least aportion of the image transfer 612 in the process of forming the writepole 602. Then, with reference to FIG. 11, the remaining image transferlayer 612 is removed such as by a tetraethylammonium hydroxide (TMAH)based etching followed by an N-methylpyrrolidinone (NMP) photoresiststrip. This leaves the first hard mask structure 603.

With reference now to FIG. 12, a layer of non-magnetic, side gapmaterial 1202 is deposited. The side gap material 1202 is preferablyalumina, although other non-magnetic materials could be used as well.This layer 1202 is preferably deposited by a conformal deposition methodsuch as atomic layer deposition, chemical vapor deposition, etc.Although various material and deposition method could be used for thelayer 1202, the layer will be referred to herein as ALD layer 1202.

Then, with reference to FIG. 13, a material removal process 1302 isperformed to remove a portion of the ALD layer 1202. The materialremoval process is preferably an ion mill, performed in an Ar chemistrywith end point detection (EPD). The third sub-layer 610 (FIG. 12) can beused to indicate when the ion milling 1302 should be terminated. Asmentioned above, the third sub-layer 610 includes an element, such asTi, that can be easily detected, such as by SIMS. Therefore, when it hasbeen determined that the third sub-layer 610 has been removed, the ionmilling 1302 can be terminated. The ton milling 1302 is preferablyperformed at an angle that is chosen remove material at a high etch rateto form an upper surface on the layers 1202, 608 that is as flat aspossible. It has been found that an optimal ion mill angle for thispurpose is about 45 to 65 degrees or about 55 degrees with respect tonormal. When the end point detection layer 608 has been reached, itspresence can be easily detected in the ion mill tool, indicating thation milling 1302 can be terminated.

Then, with reference to FIG. 14, a reactive ion etch (RIE) 1402 isperformed to remove the third sub-layer 608 leaving the first sub-layer606 exposed, and having a straight fiat surface. The RIE 1402, which maybe performed in a fluorine based chemistry, preferentially removes theend point detection layer 608, so that very little if any of the firsthard mask layer 606 is removed. This results, not only in the layer 606having a straight, fiat, surface, but also in the layer 606 having avery well controlled thickness, which thickness can be controlled atdeposition of the layer 606. With reference now to FIG. 15, a wraparound trailing shield 1502 can be formed by first depositing anelectrically conductive, magnetic seed layer and then electroplating todeposit a magnetic material. The seed layer and magnetic material canboth be, for example, NiFe. It can be seen that the thickness of thefirst sub-layer 606 defines the trailing gap thickness. However, thedeposition of the magnetic material 1502 can include first depositing anon-magnetic seed layer 1501 such as Rh or some other electricallyconductive, non-magnetic material. In that case the first sub-layerwould be deposited to a such as thickness that the thickness of thefirst sub-layer 606 plus the thickness of the seed layer 1501 togetherequal a desired trailing gap thickness. Therefore, the first sub-layeris preferably deposited to a thickness that is less than or equal to(ie. not greater than) a desired trailing gap thickness of the finishedwrite head.

FIGS. 16-18 illustrate a method of constructing a wrap around trailingmagnetic shield according to an alternate embodiment of the invention.As shown in FIG. 16, a mask structure 1602 is formed over the magneticwrite pole material layer 602.

The mask structure 1602 includes a multi-layer first hard mask structure1604. This first hard mask structure 1604 includes a first sub-layerconstructed of a non-magnetic material that is resistant to ion milling,preferably alumina (Al₂O₃). The first hard mask also includes a secondsub-layer formed over the first sub-layer, the second sub-layer beingconstructed primarily of a material that is resistant to ion milling,but which also contains a material that can be easily detected, such asby SIMS. The second sub-layer 1608 can be constructed of for examplealumina with a small amount of a detectable material such as Ti (ie.AlTiO with 1-10 atomic percent Ti). Such material, when used in thesecond sub-layer, behave much like a simple alumina hard mask (havingexcellent ion milling resistance) while also being easily detectable.

As in the previously described example, the mask structure 1602 caninclude an image transfer layer 612 formed over the hard mask layer andmay include a second, or top, hard mask layer 614, and second imagetransfer layer 616. As before, the first and second image transferlayers 612, 616 can be constructed of a soluble polyimide such asDURAMIDE®, and the top hard mask 614 can be constructed of SiO₂ or someother suitable material. The first image transfer layer 612 can have athickness of 1000 to 1400 nm or about 1200 nm. The top hard mask canhave at thickness of 100 to 130 nm or about 115 nm, and the top, orsecond, image transfer layer 616 can have a thickness of 60 to 150 orabout 90 nm. A photo mask 618 at the top of the mask structure 1602defines the width of the mask structure 1602.

As described in the above previous embodiment, an ion mill process canbe performed to form the write pole 602 and a layer of non-magneticmaterial (ALD layer) 1202 such as alumina can be deposited by aconformal deposition method, as described previously with reference toFIGS. 12 and 13.

With reference now to FIG. 17, a reactive ion milling 1302 is performedwhile detecting for the presence of the second sub-layer 1608. When ithas been determined that the second sub-layer 1608 has been removed,then milling 1302 can be terminated. The remaining first sub-layer 1606can then be left intact to provide non-magnetic trailing gap. Then, withreference to FIG. 17, a magnetic material can be deposited to form atrailing wrap around shield 1802 that does not have a notch as thepreviously described trailing shield did.

While various embodiments have been described, it should be understoodthat they have been presented by way of example only, and notlimitation. Other embodiments failing within the scope of the inventionmay also become apparent to those skilled in the art. Thus, the breadthand scope of the invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

1. A method for manufacturing a magnetic write head, comprising:providing a substrate; depositing a magnetic write pole material overthe substrate; forming a mask structure over the write pole material,the mask structure including a hard mask structure, the hard maskstructure including a first sub-layer of material that is resistant toion milling and a second sub-layer formed over the first sub-layer andcomprising alumina or diamond like carbon (DLC) and a detectablematerial, wherein the detectable material comprises an element selectedfrom the group consisting of: Ta, Ti V, Cr, Cu, Zr, Nb, Mo, Ru, Rh, Hr,W, Re, Os, Ir, Pt and Au; performing a first ion milling to removeportions of the magnetic write pole material that are not protected bythe mask structure; depositing a non-magnetic side gap material over thesubstrate, remaining write pole material and remaining mask structure;performing a second ion milling and terminating the second ion millingwhen the second sub-layer has been removed; and depositing a magneticmaterial to form a trailing shield.
 2. The method as in claim 1 furthercomprising, while performing the second ion milling, performing adetecting operation to detect the presence of the detectable material inthe second sub-layer, and terminating the second ion milling when thedetecting operation determines that the second sub-layer has beenremoved.
 3. The method as in claim 1 further comprising, whileperforming the second ion milling, performing a Secondary Ion MassSpectroscopy to detect the presence of the detectable material, andterminating the second ion milling when the Secondary Ion MassSpectroscopy indicates that the second sub-layer has been removed. 4.The method as in claim 1 wherein the second sub-layer comprises AlTiO.5. The method as in claim 1 wherein the second sub-layer comprises AlTiOwith 1-10 atomic percent Ti.
 6. The method as in claim 1 wherein thefirst sub-layer comprises alumina (Al₂O₃) and the second sub-layercomprises AlTiO with 1-10 atomic percent Ti.
 7. The method as in claim 1wherein the second sub-layer comprises 1-10 atomic percent of thedetectable material.
 8. The method as in claim 1 further comprisingdetermining a desired trailing gap thickness, the trailing gap thicknessbeing a distance between a trailing edge of the write pole and thetrailing shield, wherein the first sub-layer is deposited to a thicknessnot greater than the desired trailing gap.
 9. A method for manufacturinga magnetic write head, comprising: providing a substrate; depositing amagnetic write pole material over the substrate; forming a maskstructure over the magnetic write pole material the mask structureincluding a hard mask structure that comprises: a first sub-layercomprising a material that is resistant to ion milling; a secondsub-layer comprising a material that is resistant to ion milling, butcan be removed by reactive ion etching; and a third sub-layer comprisingalumina or diamond like carbon and a material that is detectable, thematerial that is detectable comprising an element selected from thegroup consisting of Ta, Ti, V, Cr, Cu, Zr, Nb, Mo, Ru, Rh, Hr, W, Re,Os, Ir, Pt and Au; depositing a non-magnetic side gap material over thesubstrate, write pole material and mask structure; performing an ionmilling to remove a portion of the non-magnetic side gap material andsufficiently to remove the third sub-layer; performing a reactive ionetch to remove the second sub-layer; and depositing a magnetic materialto form a trailing shield.
 10. The method as in claim 9 furthercomprising, while performing the ion milling, detecting the presence ofthe detectable material and terminating the ion milling when all of thethird sub-layer has been removed.
 11. The method as in claim 9 furthercomprising, while performing the ion milling, performing a Secondary IonMass Spectrometry (SIMS) to determine when the third sub-layer has beenremoved and terminating the ion milling when the third sub-layer hasbeen removed.
 12. The method as in claim 9 wherein the third sub-layercomprises AlTiO with 1-10 atomic percent Ti.
 13. The method as in claim9 wherein the third sub-layer comprises 1-10 atomic percent of thedetectable material.
 14. The method as in claim 9 wherein the secondsub-layer comprises Si₃N₄, SiO₂ or Ta₂O₅.
 15. The method as in claim 9wherein the removal of the second sub-layer and the deposition ofmagnetic material to form the trailing shield results in the trailingshield having a notch not greater than 30 nm deep.